This is canon...
...unless you don't believe that extra-book information is canon, in which case, these are author's notes.
I had to point out that Dean Cervantes wouldn't actually be the one giving the Rashes that warning, but that's not FPB's fault, since I haven't named the Dean of the Tenth Grade yet. But here is a partial list of my staff roster:
Charmbridge Faculty
Lilith Grimm (Dean)
Darren Ellis (Vice Dean)
Hepzibah Price (Dean of the Sixth Grade)
Caelum Black (Dean of the Seventh Grade)
Cesar Cervantes (Dean of the Eighth Grade)
Caspar Calvert (Dean of the Ninth Grade)
Artemas Beville (Dean of the Tenth Grade)
Rhea Orwell (Dean of the Eleventh Grade)
Douglas Nietz (Dean of Charmbridge Academy, 1870-1890).
Alice Minder (Librarian)
Heather Marmsley (School Secretary)
Tabitha Speaks (Bus driver)
Jean Murphy (Nurse/Healer)
Elizabeth (Libby) Gale (Groundskeeper/Custodian -- 2008-2009)
Boudica Fletcher (Groundskeeper/Custodian -- 2009-)
Teachers
William Hobbes (Transfigurations)
Alfred Newton (Charms)
Glaucus Grue (Alchemy and Potions)
Wesley Adams (Magical Principles)
Hilde Grinder (Wizarding World History)
Bethany Middle (Wizard Social Studies)
Rosemarie Gambola (P.M.E.)
Mary Shirtliffe (P.M.E. and Magical Principles)
Hypatia Hart (Magical Theory)
Vernon Bludgeleg (P.M.E.)
George Fledgefield (Magical Ecology, Magizoology)
Ceresa Verde (Magibotany, Healing)